BRUSSELS (Reuters) - Belgian police on Tuesday took in 15 people for questioning after raids as part of an investigation into the financing of militant groups and recruiting fighters for Islamic State in Syria, prosecutors said.

The raids were not linked to the Brussels attacks of March 22 in which 32 people were killed, they added in a statement.

Of the 15 people detained, four will be facing an investigating judge, prosecutors said. The raids involved police in the cities of Antwerp and Ghent in northwestern Belgium.